Search

The multiple scale of stream networks spatial organization reflects the hierarchical arrangement of streams habitats with increasingly levels of complexity from sub-catchments until entire hydrographic basins. Through these multiple spatial scales, local stream habitats form nested subsets of increasingly landscape scale and habitat size with varying contributions of both alpha and beta diversity for the regional diversity. Here, we aimed to test the relative importance of multiple nested hierarchical levels of spatial scales while determining alpha and beta diversity of caddisflies in regions with different levels of landscape degradation in a core Cerrado area in Brazil. We used quantitative environmental variables to test the hypothesis that landscape homogenization affects the contribution of alpha and beta diversity of caddisflies to regional diversity. We found that the contribution of alpha and beta diversity for gamma diversity varied according to landscape degradation. Sub-catchments with more intense agriculture had lower diversity at multiple levels, markedly alpha and beta diversities. We have also found that environmental predictors mainly associated with water quality, channel size, and habitat integrity (lower scores indicate stream degradation) were related to community dissimilarity at the catchment scale. For an effective management of the headwater biodiversity of caddisfly, towards the conservation of these catchments, heterogeneous streams with more pristine riparian vegetation found within the river basin need to be preserved in protected areas. Additionally, in the most degraded areas the restoration of riparian vegetation and size increase of protected areas will be needed to accomplish such effort.

Organic carbon performs essential functions in soils, which act as sources or sinks of atmospheric organic carbon. Agricultural management affects the carbon cycle in the soil, with effects on climate change. One of the crops most vulnerable to climate change is coffee. Brazil is the world’s largest coffee producer, with a predominance of management under a conventional system, with sloping terrain and the absence of conservationist practices. The absence of conservationist practices increases in soil loss rates due to water management and carbon emissions, as well as a reduction in coffee production. This paper intended to estimate soil and organic carbon losses by RUSLE in coffee farms in southern Minas Gerais, south-eastern Brazil. Data were obtained from fieldwork, laboratory analysis, and cartographic products. The results indicated, exclusively for coffee crops, soil and carbon losses between 7 and 32 Mg ha−1 year−1 and 87 and 460kg ha−1 year−1, respectively. However, the highest soil losses occurred on sloping terrains with eucalyptus plantations located downhill, and the lowest losses occurred on flat land with native forests. Organic carbon losses were linked directly to soil losses, as a result from the land practices, slope and agricultural management adopted. These results can be used for the planning and priority definition of areas needing conservationist practices, such as green manuring, planting in contour and maintaining of vegetation between coffee rows, which are already used in some sites of the study area. [ABSTRACT FROM AUTHOR]

Metacommunity studies have demonstrated that local macroinvertebrate communities are structured not only by local environmental conditions but also by spatial processes. Effective bioassessment tools should account for spatial processes while doing so with the least amount of cost. In this study, we applied variance partition techniques based on redundancy analysis to assess the performance of three sets of benthic invertebrate metrics in detecting agricultural land-use effects in a SE Brazil rainforest watershed. Macroinvertebrate data were analyzed separately regarding their taxonomic, functional structure and bioindicator metrics developed for the study region. We stipulated that groups of metrics most sensitive to land-use effects should have the highest amount of variance explained by the joint effects of land use and environmental variation, independently of spatial structuring. Statistical analyses were repeated removing rare taxa in order to assess the effects of their inclusion in the responsiveness of each group of metrics. Traditional bioindicator metrics were more responsive to environmental variation associated with agriculture than taxa abundances and functional attributes. Furthermore, a few common taxa drove a high proportion of the variation observed in invertebrate communities, regardless of how invertebrate data were organized. Similar analytic approaches have the potential to be useful in curtailing sorting and identification efforts when developing macroinvertebrate-based biomonitoring protocols, especially in areas where information regarding the taxonomy of benthic communities is still poorly described. [ABSTRACT FROM AUTHOR]

Anthropogenic changes in habitats are one of the main threats to biodiversity. Understanding how species diversity and their functions are affected by these changes is crucial to assess environmental impacts. In this work, we aim to understand how lizard composition, taxonomic and functional diversity respond to differences in native vegetation regeneration stages (conserved vegetation and open secondary vegetation) and agricultural land use in different vegetation types (Caatinga sensu stricto, Cerrado sensu stricto and Relictual Humid Forest) in Caatinga domain, Brazil. In more degraded areas (open secondary vegetation and agricultural areas), we found a decline in species evenness, shown by greater dominance of few species. Moreover, we found a lower functional evenness in agricultural areas than in areas of conserved vegetation, which suggests that a smaller portion of functional traits present greater dominance in more anthropized areas. We did not detect any significant differences in species richness, but we did registered differences in species composition in Relictual Humid Forest. Contrary to our expectations, lizard abundance was also greater in more degraded areas, probably as a result of the increased abundance of species benefited by anthropization. In this work, we advance the knowledge of how anthropogenic changes influence lizard diversity and emphasize the importance of analysing different facets of diversity and different habitat environments to understand how anthropization affects patterns in community ecology. [ABSTRACT FROM AUTHOR]

This work aims to develop a new method to map Land Use and Land Cover (LULC) classes in the São Paulo State, Brazil, using Landsat-8 Operational Land Imager (OLI) data. The novelty of the proposed method consists of selecting the images based on the spectral and temporal characteristics of the LULC classes. First, we defined the six classes to be mapped in the year 2020 as forest, forest plantation, water bodies, urban areas, agriculture, and pasture. Second, we visually analyzed their variability spectral characteristics over the year. Then, we pre-processed these images to highlight each LULC class. For the classification, the Random Forest algorithm available on the Google Earth Engine (GEE) platform was utilized individually for each LULC class. Afterward, we integrated the classified maps to create the final LULC map. The results revealed that forest areas are primarily concentrated in the eastern region of São Paulo, predominantly on steeper slopes, accounting for 19% of the study area. On the other hand, pasture and agriculture dominated 73% of all São Paulo's landscape, reaching 39% and 34%, respectively. The overall accuracy of the classification achieved 89.10%, while producer and user accuracies were greater than 84.20% and 76.62%, respectively. To validate the results, we compared our findings with the MapBiomas Project classification, obtaining an overall accuracy of 85.47%. Therefore, our method demonstrates its potential to minimize classification errors and offers the advantage of facilitating post-classification editing for individual mapped classes. [ABSTRACT FROM AUTHOR]

Land use is a driver for hydrological and soil erosion responses at the watershed scale. This study aimed to assess the hydrological and soil erosion processes in small watersheds under three different land uses, at three time scales. We investigated four small watersheds in southern Brazil: Agricultural North watershed (ANW), Agricultural South watershed (ASW), Eucalyptus watershed (EW), and Grassland watershed (GW). The SWAT (Soil and Water Assessment Tool) model was used to simulate streamflow (SF) and sediment yield (SY) at monthly, daily and hourly time scales. EW had the lowest SF and SY, whereas ANW showed the highest SY with an increase of 90% and ASW had the highest SF with an increase of 70%. The SWAT model had a satisfactory performance in all time scales and watersheds for SF and SY (NSE and R2 ≥ 0.3 and Pbias ≤ ± 39%). Overall, land use has a major impact on hydrological and soil erosion responses, and the magnitude of these processes depends on the time scale. [ABSTRACT FROM AUTHOR]

This work brings a refined estimation of the land use change and derived CO2 emissions associated with sugarcane cultivation, including changes in management practices and refined land-use carbon stocks, over the last two decades for Brazil's center–south and north regions. The analysis was carried out at the rural property level, considering spatially explicit land conversion data. With the refinements, we found a net carbon removal of 9.8 TgCO2∙yr−1 in sugarcane cultivation areas in the 2000–2020 period, which was due to the expansion of sugarcane over poor quality pastures (55% of the gross removals), croplands (15%) and mosaic (14%) areas, and the transition from the conventional burned harvesting to unburned (16%). Moreover, 98.4% of expansion was over existent agricultural areas. Considering all the land use changes within sugarcane-producing rural properties, the net removal is even larger, of 17 TgCO2∙yr−1, which is due to vegetation recovery. This suggests that public policies and private control mechanisms might have been effective not only to control deforestation but also to induce carbon removals associated with sugarcane cultivation. These results indicate sugarcane production system and derived products as contributors to net carbon removals in the land sector in Brazil and should be considered for both bioenergy and agricultural sustainability evaluation. [ABSTRACT FROM AUTHOR]

Developing conservation strategies to mitigate cumulative impacts requires the understanding of historic land use and land cover changes at the regional scale. By using a multisensory and multitemporal approach, we identified the major changes driving cumulative impacts on native vegetation in northeastern Amazon. Comparing two regions, one with mining as the key driver and another where mining is associated with other industrial activities (cellulose), we explore the land use and land cover historic dynamics and derive implications for the assessment of cumulative impacts. Transitions of forest cover to pastureland, silviculture, and urban expansion were mapped in detail over a 20-year period, revealing that silviculture growth cleared more forests than pastureland expansion when associated with pulp mill activities and kaolin mining. In contrast, in a region with gold and iron mining, pastureland expansion was more relevant, clearing mainly areas surrounding new roads. This research shows that the interplay of major mining and industrial investments can produce cumulative losses of native vegetation, depending on the associated industries and infrastructure required for the project development. Our findings emphasize that the definition of spatial and temporal boundaries for the assessment of cumulative impacts must consider different trends in impact accumulation and changes in their spatial distribution over time. [ABSTRACT FROM AUTHOR]

Body size influences the effect of individuals and assemblages on ecosystem functioning and defines how they respond to ecosystem changes. We evaluated how body size structure of fish assemblages and functional groups respond to human modifications at catchment, riparian and local scales in 40 streams of the Pampa grasslands, southern Brazil. To describe body size structure, we calculated the mean, coefficient of variation, skewness, and kurtosis, using individual biomass data for the entire fish assemblages and separately by functional group. The results suggested that body size response depends on body size metrics, functional group, and the spatial scale of land use. From 11 functional groups, only five showed a clear response to land use. In general, most functional groups had a higher concentration of small sizes (left-skewed) in response to increased land use measured at distinct spatial scales (local, riparian, and catchment), and a greater concentration of sizes in a narrow and central distribution (higher kurtosis). However, the responses were complex and varied between the functional groups. We conclude that considering ecomorphological and trophic features separately by functional group and assessing multiple body size metrics contributed greatly to detecting the influence of land use on fish body size. [ABSTRACT FROM AUTHOR]

Due to its low share of energy-related emissions, energy systems models have overlooked the implications of technological transition in the agricultural sector and its interaction in the wider energy system. This paper explores the role of agriculture intensification by using a novel agricultural-based energy systems model. The aim is to explore the future role of Brazil's agriculture and its dynamics with other energy sectors under two carbon constraint scenarios. The main focus has been to study resource competition between sugarcane and natural gas at a country level. Results show that in order to meet the future food and bioenergy demand, the agricultural sector would start intensifying by 2030, improving productivity at the expense of higher energy demand, however, land-related emissions would be minimised due to freed-up pasture land and reduction in deforestation rates. Additionally, the development of balanced bioenergy and natural gas markets may help limit the sugarcane expansion rates, preserving up to 12.6 million hectares of forest land, with significant emissions benefits. [ABSTRACT FROM AUTHOR]

Introduction: Aquatic ecosystems in southern Brazil are presently under great environmental pressure. Changes in land use result in negative impacts on the ecosystem, affecting the functioning of stream communities. Objective: To compare the benthic macroinvertebrate community richness, abundances and compositions in streams of three South Brazilian grassland landscapes and correlate community patterns with environmental and spatial variables. Methods: Fifteen streams along riparian forests were selected in three landscapes (mean geographical distance of 285.1 km) inserted in the Paraná and Uruguai river basins. Of the three landscapes, two are inserted in conservation units (State Park of Guartelá and Palmas Wildlife Refuge). Invertebrates were collected in 20 kick net points along 150 m of the streams between June and November 2015. Invertebrates were sorted in the laboratory with three sieves and were identified to the lowest taxonomic level possible. The taxa were classified in functional feeding groups of shredders/detritivores, predators, scrapers, collectors/filters and gatherers/collectors. For each stream, we measured the environmental variables width and velocity, pH, dissolved oxygen, and temperature; and the relative cover of forest, grassland, plantation and silviculture in the catchments. Results: We found a total of 1 058 individuals, divided in 53 morphospecies and 34 families. Lower abundance of benthic macroinvertebrates was found in the northernmost landscape with higher temperature, and forest in the catchment. These streams were described mainly by predator groups, while streams inserted in the other two landscapes showed a more diverse guild composition of shredders/detritivores, gatherers/collectors, collectors/filterers, and scrapers. Geographical distance was the main factor influencing differences in community compositions among landscapes. Conclusions: Lower abundance of the northernmost landscape may be explained by (i) the low habitat heterogeneity due to dominance of sandy substrates, and by (ii) the anthropogenic land use of agriculture and extensive cattle breeding in the region that is ongoing and started before the creation of the conservation unit. Additionally, composition of macroinvertebrates may be correlated with environmental differences among landscapes that, in turn, are related to the geographical distance. Therefore, macroinvertebrate community responses may reflect different biota biogeographical histories that can also be associated with historical land use practices. [ABSTRACT FROM AUTHOR]

This paper presents a dataset of yearly land use and land cover classification maps for Mato Grosso State, Brazil, from 2001 to 2017. Mato Grosso is one of the world's fast moving agricultural frontiers. To ensure multi-year compatibility, the work uses MODIS sensor analysis-ready products and an innovative method that applies machine learning techniques to classify satellite image time series. The maps provide information about crop and pasture expansion over natural vegetation, as well as spatially explicit estimates of increases in agricultural productivity and trade-offs between crop and pasture expansion. Therefore, the dataset provides new and relevant information to understand the impact of environmental policies on the expansion of tropical agriculture in Brazil. Using such results, researchers can make informed assessments of the interplay between production and protection within Amazon, Cerrado, and Pantanal biomes. Measurement(s) land • land use Technology Type(s) computational modeling technique Factor Type(s) year • geographic location • land use and cover class Sample Characteristic - Environment land Sample Characteristic - Location Mato Grosso State Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.11440461 [ABSTRACT FROM AUTHOR]

Due to its low global share of direct energy consumption and greenhouse gas emissions (1–2%), the implications of technological transitions in the agricultural and forestry sector on the energy system have been overlooked. This paper introduces the Agriculture and Land Use Sector module part of the ModUlar energy System Environment (MUSE), a novel energy system simulation model. The study presents a generalisable method that enables energy modellers to characterise agricultural technologies within an energy system modelling framework. Different mechanisation processes were characterised to simulate intensification/extensification transitions in the sector and its wider implications in the energy and land use system aiming at providing reliable non-energy outputs similarly to those found in dedicated land use models. Additionally, a forest growth model has been integrated to explore the role of reforestation alongside decarbonisation measures in the energy system in achieving carbon mitigation pathways. To illustrate the model's capabilities, Brazil is used as case study. Outputs suggest that by 2030 under a 2 °C mitigation scenario, most of Brazil agricultural production would move from 'transitional' to 'modern' practices, improving productivity and reducing deforestation rates, at the expense of higher energy and fertiliser demand. By mid-century Brazil has the potential to liberate around 24.4 Mha of agricultural land, where large-scale reforestation could have the capacity to sequester around 5.6 GtCO 2 , alleviating mitigation efforts in the energy system, especially reducing carbon capture and storage technology investments in the industry and power sector. • A novel energy-oriented agriculture and land use systems model has been developed. • Mechanisation levels are characterised using cluster analysis and linear optimisation. • Role of reforestation alongside measures in the energy sector in Brazil are studied. • By 2050, modern mechanisation could represent 54–63% of agricultural production. • Brazil has the potential to sequester around 5.6 GtCO 2 through reforestation. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Brazilian Cerrado area is in rapid decline because of the expansion of modern agriculture. In this study, we used extensive field data and a 30-year chronosequence of Landsat images (1980-2010) to assess the effects of time since conversion of Cerrado into agriculture upon soil chemical attributes and soybean/corn yield in the Alto do Rio Verde watershed. We determined the rates of vegetation conversion into agriculture, the agricultural land use time since conversion, and the temporal changes in topsoil (0-20 cm soil depth) and subsurface (20-40 cm) chemical attributes of the soils. In addition, we investigated possible associations between fertilization/over-fertilization and land use history detected from the satellites. The results showed that 61.8% of the native vegetation in the Alto do Rio Verde watershed was already converted into agriculture with 31% of soils being used in agriculture for more than 30 years. While other fertilizers in cultivated soils (e.g., Ca, Mg, and P) have been compensated over time by soil management practices to keep crop yield high, large reductions in C (38%) and N (29%) were observed in old cultivated areas. Furthermore, soybean and cornfields having more than 10 years of farming presented higher values of P and Mg than the ideal levels necessary for plant development. Therefore, increased risks of over-fertilization of the soils and environmental contamination with these macronutrients were associated with soybean and cornfields having more than 10 years of farming, especially those with more than 30 years of agricultural land use. [ABSTRACT FROM AUTHOR]

Given that sustainability of Brazilian ethanol is intrinsically associated with the effects of sugarcane expansion on land use changes, this paper aims to assess sugarcane land use using data such as sugarcane yield, water requirements, land expansion and production costs under rainfed and irrigated management. The Paranaíba basin was selected as a case study because of recent large scale expansion of sugarcane. Enhanced Vegetation Index (EVI) methodology was used to identify sugarcane dynamics during four crop seasons. Crop water requirements, through the water footprint methodology, cane yield, and production costs were estimated by combining the Agroecological Zone Model and CanaSoft. Results show that most sugarcane was spatially distributed in the central area of the basin, with less potential for yield gain through irrigation. This region has significant water availability issues. A 54% increase in sugarcane area (617,000–947,000 ha) was identified, mostly from the central region to the west, and to a lesser extent to the southeast. Both expansion areas represent improved edaphoclimatic (soil and climatic) conditions, hence, higher yields, lower water footprint, and lower production costs under rainfed and irrigated managements. Furthermore, there are less subbasins with water quantity problems and almost none with water quality or both quantity and quality concerns, which suggests greater possibilities for accessing water for irrigation; however, there is an environmental cost associated with this practice on average, 13 m 3 Mg −1 (Mega gram, 10 6 g) of blue water footprint. In the context of this highly water-intensive crop, sugarcane expansion in the Paranaíba basin in areas of improved soil and climatic conditions enhances the sustainability of ethanol production in Brazil. [ABSTRACT FROM AUTHOR]

Because of their strong dependence on the environment, the spatial distribution of pond-breeding amphibians can be greatly influenced by anthropogenic habitat alteration. In some agricultural landscapes in Brazil, the anuran Pseudopaludicola mystacalis appears to be highly influenced by land use. Because adult males and tadpoles of this species are usually found in marshy areas with cattle hoof prints, we hypothesized that P. mystacalis preferentially occupies aquatic habitats with marshy areas that are trampled by cattle. To test our hypothesis, we assessed whether the occurrence of P. mystacalis is associated with the presence of cattle and trampled marshy areas, and which environmental features best explain the spatial distribution and abundance of P. mystacalis. To do so, we sampled 38 aquatic habitats in an area intensely used for livestock in southeastern Brazil. We found that the presence of cattle and trampled marshy areas in aquatic habitats are positively associated to P. mystacalis occurrence. Additionally, the abundance of calling males is better predicted by variables of landscape and local habitat structure. Specifically, the size of trampled marshy areas and the proportion of herbaceous vegetation within the aquatic habitat are positively associated with abundance, while distance to nearest aquatic habitat are negatively associated with abundance of calling males. All three of these variables can be directly or indirectly linked to the presence of cattle or grazing management. Therefore, this work shows evidence that Pseudopaludicola mystacalis is positively influenced by grazing management with cattle, and draws attention to other unknown potential consequences of different land use to fresh water diversity. [ABSTRACT FROM AUTHOR]

Increasing demand for biofuel has intensified land-use change (LUC) for sugarcane (Saccharum officinarum) expansion in Brazil. Assessments of soil quality (SQ) response to this LUC are essential for quantifying and monitoring sustainability of sugarcane production over time. Since there is not a universal methodology for assessing SQ, we conducted a field-study at three sites within the largest sugarcane-producing region of Brazil to develop a SQ index (SQI). The most common LUC scenario (i.e., native vegetation to pasture to sugarcane) was evaluated using six SQI strategies with varying complexities. Thirty eight soil indicators were included in the total dataset. Two minimum datasets were selected: one using principal component analysis (7 indicators) and the other based on expert opinion (5 indicators). Non-linear scoring curves were used to interpret the indicator values. Weighted and non-weighted additive methods were used to combine individual indicator scores into an overall SQI. Long-term conversion from native vegetation to extensive pasture significantly decreased overall SQ. In contrast, conversion from pasture to sugarcane had no significant impact on overall SQ at the regional scale, but site-specific responses were found. In general, sugarcane production improved chemical attributes (i.e., higher macronutrient levels and lower soil acidity); however it has negative effects on physical and biological attributes (i.e., higher soil compaction and structural degradation as well as lower soil organic carbon (SOC), abundance and diversity of macrofauna and microbial activity). Overall, we found that simple, user-friendly strategies were as effective as more complex ones for identifying SQ changes. Therefore, as a protocol for SQ assessments in Brazilian sugarcane areas, we recommend using a small number of indicators (e.g., pH, P, K, Visual Evaluation of Soil Structure -VESS scores and SOC concentration) and proportional weighting to reflect chemical, physical and biological processes within the soil. Our SQ evaluations also suggest that current approaches for expanding Brazilian sugarcane production by converting degraded pasture land to cropland can be a sustainable strategy for meeting increasing biofuel demand. However, management practices that alleviate negative impacts on soil physical and biological indicators must be prioritized within sugarcane producing areas to prevent unintentional SQ degradation over time. [ABSTRACT FROM AUTHOR]

Brazil has dramatically increased its agricultural area under cultivation, in the process becoming a major food exporter at the cost of natural forests. A new challenge is to meet the food demands of an expanding world population in the face of pessimistic climate change scenarios and the increasing scarcity of land. Can Brazil help meet rising world food demand while conserving its tropical rainforests? To address this question we simulate outcomes using a large dynamic multiregional computable general equilibrium model of Brazil to model land use over 20 years in 90 zones and 14 agricultural sectors. The model features a land-use change module based on a transition matrix obtained from satellite imagery. We analyze two scenarios of deforestation reduction, both linked to actual policy proposals. Model results indicate several mechanisms that allow food output to increase without expanding land supply. In particular, we stress the role of Brazil's vast, low-yield pasture area as a source of future cropland. Thus, we find that controlling deforestation leads to rather small decreases in food output--which could be neutralized by tiny exogenous productivity improvements. We conclude that the decrease in deforestation will not significantly compromise Brazilian agricultural supply capacity in the foreseeable future. [ABSTRACT FROM AUTHOR]

Soybean farming has brought economic development to parts of South America, as well as environmental hopes and concerns. A substantial hope resides in the decoupling of Brazil's agricultural sector from deforestation in the Amazon region, in which case expansive agriculture need not imply forest degradation. However, concerns have also been voiced about the potential indirect effects of agriculture. This article addresses these indirect effects for the case of the Brazilian Amazon since 2002. Our work finds that as much as thirty-two percent of deforestation, or the loss of more than 30,000 km 2 of Amazon forest, is attributable, indirectly, to Brazil's soybean sector. However, we also observe that the magnitude of the indirect impact of the agriculture sector on forest loss in the Amazon has declined markedly since 2006. We also find a shift in the underlying causes of indirect land use change in the Amazon, and suggest that land appreciation in agricultural regions has supplanted farm expansions as a source of indirect land use change. Our results are broadly congruent with recent work recognizing the success of policy changes in mitigating the impact of soybean expansion on forest loss in the Amazon. However, they also caution that the soybean sector may continue to incentivize land clearings through its impact on regional land markets. [ABSTRACT FROM AUTHOR]

Construction of the Itaparica dam and reservoir induced changes in the agricultural production systems of the Itaparica micro-region, at the lower-middle São Francisco river basin. Extensive traditional systems were replaced by e.g. irrigated fruit production. However, over twenty years after the dam construction, many farmers are still facing income insecurity. A survey, consisting of expert interviews and structured on-farm interviews, has been conducted to analyze current production systems. A Linear Programming farm optimization model was applied to determine optimal land allocation considering changing production conditions. Income depended strongly on low wages for day laborers, free irrigation water, and stable prices of the main crop, coconut. Diversification of production and improved market access can help to improve farmers' income situation. Moderate water pricing can raise the awareness of water scarcity and lead to implementation of water saving production methods. [ABSTRACT FROM AUTHOR]

Covering almost a quarter of Brazil, the Cerrado is the world’s most biologically rich tropical savanna. Fire is an integral part of the Cerrado but current land use and agricultural practices have been changing fire regimes, with undesirable consequences for the preservation of biodiversity. In this study, fire frequency and fire return intervals were modelled over a 12-year time series (1997–2008) for the Jalapão State Park, a protected area in the north of the Cerrado, based on burned area maps derived from Landsat imagery. Burned areas were classified using object based image analysis. Fire data were modelled with the discrete lognormal model and the estimated parameters were used to calculate fire interval, fire survival and hazard of burning distributions, for seven major land cover types. Over the study period, an area equivalent to four times the size of Jalapão State Park burned and the mean annual area burned was 34%. Median fire intervals were generally short, ranging from three to six years. Shrub savannas had the shortest fire intervals, and dense woodlands the longest. Because fires in the Cerrado are strongly responsive to fuel age in the first three to four years following a fire, early dry season patch mosaic burning may be used to reduce the extent of area burned and the severity of fire effects. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Global energy demand will increase through the twenty-first century. Competition for energy resources has already revealed geopolitical fault lines, and the dependence of industrial economies on fossil fuel promises to keep nations on edge. A widespread consensus has emerged that societies must transition to a new energy basis, given that fossil fuel is nonrenewable and its combustion leads to global warming. Although alternatives like nuclear energy and hydropower provide important electrical supplies locally, the search goes on, and recently much attention has focused on biofuel. Although biofuel represents a renewable and 'green' energy, there is also a downside. This article considers one potential problem, namely, the impact of growing international biofuel demand on Amazonia. The article focuses on Brazil, given the explosive growth of Brazilian agriculture, and notable effects on forests within its national borders. The article seeks to answer this question: How will global demand for Brazil's land-based commodities, including biofuel, impact its tropical forest in the Amazon basin? In attempting to answer this question, the article describes recent agricultural expansion in Brazil and its emergent landscape of renewable energy. Using an adaptation of rent theory, it frames a concept of landscape cascade and shows how Brazil's expanding landscape of renewable energy is impacting forest areas at a great distance. The article then considers recent projections of demand for Amazonian land out to 2020, given growth of Brazilian biofuel production and cattle herds. The projections indicate that more Amazonian land will be demanded than has been made available by Brazilian environmental policy. With this result in mind, the article discusses the discursive dismemberment of Amazonia and how this articulates with efforts by Brazilian politicians to increase the region's land supply. The article points out that agricultural intensification holds the key to meeting global demand without degrading the Amazonian forest, a landscape unique in the world for its ecological and cultural riches. [ABSTRACT FROM AUTHOR]

Agricultural development and climate change will be two of the major stressors on the Amazon natural-human system in the decades to come. Environmental licensing for rural properties is being implemented in several states in the Brazilian Amazon with the goal of restoring forests in agricultural landscapes and mediating the impacts of these stressors. This study presents an agent-based model of ranching and land exchange, informs it with empirical results from social research in the Ji-Paraná River Basin, Rondônia, Brazil, and investigates the social, economic, and environmental outcomes that can be expected as a result of environmental licensing in the context of climate change. Model results informed by these data suggest that although an environmental licensing scheme with monitoring and enforcement may increase the level of forested land in ranching landscapes, it may do so at the expense of the small producer. To the extent that effective monitoring and enforcement exist, a focus on larger holdings will help to mediate this negative social impact. These results suggest that a middle ground can be found in cases where current environmental goals conflict with legacies of past colonization and resource-use regimes. [ABSTRACT FROM AUTHOR]

Maintenance of soil quality is a key component of agriculture sustainability and a main goal of most farmers, environmentalists and government policymakers. However, as there are no parameters or methods to evaluate soil quality directly, some attributes of relevant soil functions are taken as indicators; lately, an increase in the use of soil microbial parameters has occurred, and their viability as indicators of proper land use has been highlighted. In this study we performed a meta-analysis of the response ratios of several microbial and chemical parameters to soil disturbance by different land uses in the Brazilian biomes. The studies included native forests, pastures and perennial and annual cropping systems. The introduction of agricultural practices in all biomes covered previously with natural vegetation profoundly affected microbial biomass-C (MB-C)-with an overall decrease of 31%. Annual crops most severely reduced microbial biomass and soil organic C, with an average decrease of 53% in the MB-C. In addition, the MB-C/TSOC (total soil organic carbon) ratio was significantly decreased with the transformation of forests to perennial plantation (25%), pastures (26%), and annual cropping (20%). However, each biome reacted differently to soil disturbance, i.e., decreases in MB-C followed the order of Cerrado>Amazon>Caatinga>Atlantic Forest. In addition, the Cerrado appeared to have the most fragile soil ecosystem because of lower MB-C/TSOC and higher qCO. Unfortunately, the Cerrado and the Amazon, demonstrated by our study as the most fragile biomes, have been subjected to the highest agronomic pressure. The results reported here may help to infer the best land-use strategies to improve soil quality and achieve agriculture sustainability. The approach can also be very useful to monitor soil quality in other tropical and subtropical biomes. [ABSTRACT FROM AUTHOR]

We examine how access regimes, defined by a set of interrelated institutions and organizations, facilitated the flow of production resources and benefits that resulted in patterns of land change in the Brazilian Cerrado. We analyzed remotely sensed data (Landsat MSS, TM, +ETM) for three time periods (1972/1973-1986, 1986-1992, 1992-2002) with qualitative and archival data for eastern Mato Grosso state. Overall we found that land privately colonized was cleared more rapidly and extensively than lands under no colonization scheme. We also identified significant spatial variability in Cerrado conversion within and outside colonization areas and variability of annual rates of Cerrado conversion during each period. We explain that farmers in the Cerrado engaged in land-leasing and production contracts and worked through cooperatives and firms to marshal resources, including credit, technology, and inputs, which, in turn, influenced land-use decisions and regional patterns of land-cover change. We conclude that a mesoscale analytical framework that examines how land managers access natural and productive resources provides useful insights to explain the processes that cause patterns of high-input agricultural expansion. [ABSTRACT FROM AUTHOR]

Demographic interest in population and environment has grown in recent decades. One of the most prominent research areas in this tradition addresses the impact of population on land use and land cover change. Building on this tradition, we examine the effects of household demographic composition on land use and land cover on small farms in two study areas in the Brazilian Amazon. Fixed effects regression models of used area and forested area show few consistent effects of changes in household demography on land use and land cover change. Effects are inconsistent with the household life cycle model that currently dominates the literature on household demographic effects in frontiers. Changes in the number of children and women, particularly young women, have the most significant effects on land use and land cover change. We conclude by arguing that households strategically access cash for investment in agriculture and that specific strategies are determined by economic and institutional context. [ABSTRACT FROM AUTHOR]

The recent rise in Brazilian soybean production has generated concern among the environmental community and some authors that natural tropical environments of the Amazon Basin are being converted to soybean fields. Proponents of soybean production counter that soybeans represent a viable agricultural commodity for the region; environmental concern is unwarranted, because new soybean fields are replacing already deforested or other- wise transformed lands. Both arguments have been made without comprehensive study and measure of land-use/land-cover (LULC) in areas undergoing expansion of soybean production. This case study, conducted in the municipality of Vilhena, Rondônia, Brazil, in the southwestern Amazon Basin, uses remote sensing to evaluate the LULC accompanying this municipality's large growth in soybean production from 1996 to 2001. Forests are being converted for soybean production, but most of the production increase appears attributable to slight expansion of already existing fields, conversion of already deforested land, and higher yields. [ABSTRACT FROM AUTHOR]

This article examines transformations associated with changes in resource use and land cover dynamics in the community of São Manoel, Maranhão state, in the eastern Brazilian Amazon. The shifting cultivator peasants in São Manoel integrate swidden fields for annual cropping, the extraction of babassu palm products, and pastures for cattle ranching. Since the early twentieth century, predominant vegetative cover patterns have been altered from species-rich mature forests to secondary succession with babassu dominant to pasture or swidden fields containing palm stands of various densities. A grounded political ecology of resource use in the area suggests that management strategies and the resulting land cover dynamics integrate site-specific decisions of peasant producers. I discuss the trajectory of production strategies in São Manoel since the establishment of the community in the 1920s, and identify the multiple dimensions affecting resource use and environmental outcomes, with an emphasis on the period following land struggles and the recovery of peasant tenure rights in the mid-1980s. The analysis indicates that socionatural trajectories that optimize resource use and address the socioeconomic needs of the community include the maintenance of palm/pastures associations. [ABSTRACT FROM AUTHOR]

In recent years, scholars of “contentious politics” have paid increasing attention to the dynamics of space and place in the construction of organized resistance. To date, however, the literature has tended to focus on the social construction of space rather than the equally important spatial constitution of the social. In this paper, I analyze how particular understandings of space, or what I call “spatial imaginaries”—cognitive frameworks, both collective and individual, constituted through the lived experiences, perceptions, and conceptions of space itself—influenced the formation of the largest grassroots social movement in Brazilian history, the Movement of Rural Landless Workers (the MST). I analyze the decision to join the MST among small family farmers in southern Brazil and rural plantation workers in northeastern Brazil. People from both groups decided to join the movement, but the farmers from southern Brazil used their spatial imaginaries to embrace the act of occupying land and to create new frontiers for colonization while the rural workers from northeastern Brazil overcame the spatial imaginaries produced through the plantation labor system and joined the movement because they had few other options available to them. Because such imaginaries stay with people long after they engage in the initial acts of mobilization, incorporating this sort of analysis introduces an important dynamic component into the analysis of movement formation. [ABSTRACT FROM AUTHOR]

Since the 1970s the Brazilian Amazon has received over 1 million migrant farm households from other regions of the country, many of whom were attracted to government-sponsored frontier settlement programs that offered free tropical forest land. As a result, pressures on tropical forests have intensified along several settlement corridors throughout the region. Despite their importance as agents of landscape change, surprisingly little is known about the land use practices of these farmers. This paper briefly reviews the research literature on smallholder land use patterns in Amazonia, describes the recent history of one important agricultural land settlement program in the western Brazilian Amazon state of Rondônia, and, based on 240 household surveys conducted in three separate settlement locations in the state, highlights key differences in land use patterns among the rural population. Typologies of farming systems are presented on the basis of cluster analysis of land use data and ANOVA tests. The findings indicate considerable complexity and heterogeneity in smallholder farming systems. Spatial variations in farming system types may be due to geographic differences in soil regimes, the social histories of specific communities, and site-specific responses to exogenous variables. [ABSTRACT FROM AUTHOR]

Anthropogenic N inputs and riverine export were determined for a meso-scale river basin in one of the most developed and economically important regions of South America. The Piracicaba River basin is located in southeastern Brazil and drains into a tributary of the Paraná River. The basin supports over 3 million people (about 2% of the population of Brazil) with intensive agricultural and industrial activities. During two years from 1995 to 1997, biweekly samples were collected at 10 stations along the Piracicaba River and its tributaries for analyses of dissolved and particulate N. The average annual flux of dissolved inorganic N and total N increased by a factor of 15 and 20 times, respectively, from the headwaters to the lower reaches of the main channel, whereas discharge increased by only 7 times. On a per area basis, the export of TN varied according to land use and was significantly correlated to the net input of anthropogenic N. Among 10 sub-catchments composing the basin, areas mostly covered by pasture and forest had the lowest export, whereas more agricultural and urban areas had higher export. The amount of N exported from each sub-catchment varied widely, but inputs were consistently higher than fluvial outputs. Losses and retention of N occurred throughout the basin but were especially high in the sub-catchment with a main-stem reservoir, suggesting that aquatic processing plays an important role in controlling riverine N export. Total net anthropogenic input to the Piracicaba River basin was 4,500 (± 900) kg N km-2 yr-1 of which about 40% was exported via fluvial outputs. [ABSTRACT FROM AUTHOR]

The article discusses increase in agricultural production of Brazil and its impact on Amazon, Brazil. It states that its beef export has increased and it is competing with the U.S. for the title of largest soya exporter in the world. Inspite increase in its crops, deforestation of Amazon has been less. Brazil is practicing a sustainable agricultural system which helps to maintain balance between food and environment. Soybeans is reportedly its largest food crop, worth 17 billion dollars in 2008 and it has also made genetically modified (GM) of soya beans. It mentions that Brazil is making careful use of land like its soybeans exporters agreed a moratorium on trade of soybeans grown on land which was deforested after July 2006.

Seasonally dry tropical forests are strongly impacted by human activities such as agriculture and ranching, as well as variations in climate conditions. Soil nematodes are sensitive to these changes, given that soil and climate characteristics influence their survival and occurrence. We analyzed the changes in the structure of nematode communities in three different types of land use (agricultural areas, secondary forest and natural forest) in the Caatinga, at Catimbau National Park, Pernambuco, northeastern Brazil. We recorded a total of 17,177 nematode individuals belonging to 104 genera. Nematode abundance and richness were highest in the secondary forest and lowest in the agricultural areas. The total abundance of bacterivores and omnivore-predators was affected by types of land use. Different soil properties as well as monthly mean rainfall and temperature were strongly related to the differences in taxonomic composition among the agricultural areas, secondary forest and natural forest, accounting for 65.42% of the total variation. In general, our results indicate that agricultural activities in the Caatinga negatively affect the nematode communities, and that soil characteristics and climate variables also strongly affect the structure and composition of these communities. • The agricultural activities negatively affect the nematode communities. • The secondary forest regenerating increases the nematode abundance. • Bacterivorous nematodes Acrobeles spp. dominated in various types of land use. • The nematode composition was related to soil properties and climate variables. • The nematode community can be used to assess soil health in Caatinga. [ABSTRACT FROM AUTHOR]